The logic of equivalence testing and its use in laboratory medicine

Predictability of anterior open bite treatment with Invisalign

INTRODUCTION

Anterior open bite correction with Invisalign has been claimed to have relatively good predictability because of the proposed function of clear aligners to function as occlusal bite-blocks, limiting extrusion of the posterior teeth or possibly even intruding posterior teeth. This proposal, however, remains relatively unsubstantiated. The objective of this study was to investigate and determine the accuracy of Invisalign treatment in correcting anterior open bite by comparing the predicted outcome from ClinCheck to the achieved outcome for the initial aligner sequence.

METHODS

A retrospective study used pretreatment and posttreatment intraoral scans and predicted outcomes (ClinCheck) stereolithography files of 76 adult patients from private specialist orthodontic practices. Inclusion criteria comprised nonextraction treatment, with a minimum of 14 dual arch Invisalign aligners. Geomagic Control X software was used to measure overbite and overjet in the pretreatment, posttreatment, and predicted outcomes stereolithography files for each patient.

RESULTS

Approximately 66.2% of the programmed open bite closure was expressed compared with the prescribed ClinCheck outcome. The use of posterior occlusal bite-blocks and prescribed movement of teeth via anterior extrusion, posterior intrusion, or a combination of the 2 made no difference to the efficacy of open bite closure. Two-week aligner changes resulted in 0.49 mm more bite closure on average.

CONCLUSIONS

The prescribed bite closure in ClinCheck software overestimates the bite closure that is clinically achieved.

How to Choose between Different Bayesian Posterior Indices for Hypothesis Testing in Practice

Hypothesis testing is an essential statistical method in experimental psychology and the cognitive sciences. The problems of traditional null hypothesis significance testing (NHST) have been discussed widely, and among the proposed solutions to the replication problems caused by the inappropriate use of significance tests and p-values is a shift toward Bayesian data analysis. However, Bayesian hypothesis testing is concerned with various posterior indices for significance and the size of an effect. This complicates Bayesian hypothesis testing in practice, as the availability of multiple Bayesian alternatives to the traditional p-value causes confusion which one to select and why. In this paper, various Bayesian posterior indices which have been proposed in the literature are compared and their benefits and limitations are discussed. The comparison shows that conceptually not all proposed Bayesian alternatives to NHST and p-values are beneficial, and the usefulness of some indices strongly depends on the study design and research goal. However, the comparison also reveals that there exist at least two candidates among the available Bayesian posterior indices which have appealing theoretical properties and are widely underused in the cognitive sciences.

Predictability of overbite control with the Invisalign appliance comparing SmartTrack with precision bite ramps to EX30

INTRODUCTION

Although the Invisalign appliance has reported difficulty in achieving the overbite outcomes predicted by ClinCheck software (Align Technology, Santa Clara, Calif), the effect of modifications to the material and components of the appliance are largely unquantified. This study aimed to investigate and determine the accuracy of Invisalign in correcting a deep overbite by comparing the predicted outcome from ClinCheck to the achieved posttreatment outcome for treatment groups that use different components of the appliance system.

METHODS

A retrospective study was conducted using pretreatment and posttreatment intraoral scans and predicted outcomes (ClinCheck) stereolithography files of 2 groups of consecutively treated adult patients from private specialist orthodontic practices, 1 group treated with EX30 material with no bite ramps (n = 29) and 1 treated with the newer SmartTrack material and precision bite ramps (n = 39). Inclusion criteria comprised nonextraction treatment, with a minimum of 14 dual arch Invisalign aligners using a 2-weekly aligner change protocol. Geomagic Control X software (3D Systems, Rock Hill, SC) was used to measure overbite in the pretreatment, posttreatment, and predicted outcome stereolithography files for each patient. Results were compared with a previously published treatment group that used SmartTrack material and no precision bite ramps.

RESULTS

The regression coefficient analysis indicated that for both groups, the deeper the pretreatment overbite and the greater overbite reduction projected according to ClinCheck, there is a linear increase in the discrepancy of overbite expression posttreatment. ClinCheck overpredicted overbite reduction in 96.6% of patients with precision bite ramp in which, on average, 43.4% of the prescribed overbite reduction was expressed. For EX30 patients, ClinCheck overpredicted overbite reduction in 87.2% of patients in which, on average, 55.1% of the prescribed overbite reduction was expressed.

CONCLUSIONS

The use of precision bite ramps does not appear to significantly improve the ability of SmartTrack material to predictably open the bite. SmartTrack material with or without bite ramps does not appear to produce better bite opening predictability than that seen with EX30 material.

Impact of language proficiency on mental health service use, treatment and outcomes: "Lost in Translation"

BACKGROUND

Mastery of a language is bound to place of origin; low language proficiency is thus related to migration and cultural differences, all of which influence access to mental health care, treatment and outcomes. Switzerland, being multilingual, allows the disentangling of language proficiency from migration and, to some extent, culture. This study uses propensity score matching to explore how language proficiency relates to help-seeking behaviour, service use, treatment and outcomes in patients with mental health disorders.

METHODS

We used the first admission of patients admitted to and discharged from an academic psychiatric hospital in Switzerland between January 1st, 2013 and December 31st, 2019, with an observation period of one-year post-discharge (until December 31st, 2020). We paired 2101 patients with low language proficiency to 2101 language proficient patients, balancing baseline sociodemographic and clinical characteristics using propensity score matching.

RESULTS

Patients with low language proficiency had a higher probability of compulsory admission (OR: 1.79, 99%CI: 1.60-2.02); which remained after adjustment for confounders (OR: 1.51; 99%CI: 1.21-1.89). Whilst in treatment, they had higher rates of compulsory medication (OR: 1.73, 99%CI: 1.16-2.59) and seclusion/restraint (OR: 1.87, 99%CI: 1.25-2.79). Furthermore, patients initially admitted voluntarily had a higher probability of being compulsorily retained (OR: 1.74, 99%CI: 1.24-2.46). Both groups showed similar clinical improvement rates and service use parameters.

CONCLUSIONS

Our results demonstrate that low language proficiency constitutes a risk factor for coercive measures throughout hospitalisation. The results demonstrate the need for an increase in language sensitivity in psychiatric care.

Impact of Compulsory Admission on Treatment and Outcome: A Propensity Score Matched Analysis

Background

Despite multiple ethical issues and little evidence of their efficacy, compulsory admission and treatment are still common psychiatric practice. Therefore, we aimed to assess potential differences in treatment and outcome between voluntarily and compulsorily admitted patients.

Methods

We extracted clinical data from inpatients treated in an academic hospital in Zurich, Switzerland between January 1, 2013 and December 31, 2019. Observation time started upon the first admission and ended after a one-year follow-up after the last discharge. Several sociodemographic and clinical characteristics, including Health of the Nation Outcome Scales (HoNOS) scores, were retrospectively obtained. We then identified risk factors of compulsory admission using logistic regression in order to perform a widely balanced propensity score matching. Altogether, we compared 4,570 compulsorily and 4,570 voluntarily admitted propensity score-matched patients. Multiple differences between these groups concerning received treatment, coercive measures, clinical parameters, and service use outcomes were detected.

Results

Upon discharge, compulsorily admitted patients reached a similar HoNOS sum score in a significantly shorter duration of treatment. They were more often admitted for crisis interventions, were prescribed less pharmacologic treatment, and received fewer therapies. During the follow-up, voluntarily admitted patients were readmitted more often, while the time to readmission did not differ.

Conclusions

Under narrowly set circumstances, compulsory admissions might be helpful to avert and relieve exacerbations of severe psychiatric disorders.

Predictability of overbite control with the Invisalign appliance

INTRODUCTION

Control of overbite is considered essential in achieving ideal orthodontic outcomes. Questions have been raised regarding the accuracy of ClinCheck software (Align Technology, Santa Clara, Calif) in predicting posttreatment outcomes with Invisalign, with the paucity of well-researched literature available on this topic. This research aimed to investigate and determine the accuracy of Invisalign (Align Technology) in correcting a deep overbite by comparing the outcomes predicted by ClinCheck with achieved posttreatment outcomes.

METHODS

A retrospective study was conducted using pretreatment and posttreatment intraoral scans and predicted outcome (ClinCheck) stereolithography files of 42 adult patients consecutively treated with Invisalign from January 2014 and completed before July 2018, selected from the files of 1 experienced orthodontist. Patients included in the study were treated without extractions and with a minimum of 14 dual arch Invisalign aligners using a 2-weekly aligner change protocol. The pretreatment, posttreatment, and predicted outcome stereolithography files for each patient were imported into Geomagic Control X (3D Systems, Rock Hill, SC) software to measure overbite.

RESULTS

The deeper the patient's initial overbite and the greater the amount of programmed reduction in overbite according to ClinCheck, the greater the discrepancy in overbite expression posttreatment. ClinCheck over-predicted overbite reduction in 95.3% of patients in which, on average, only 39.2% of the prescribed overbite reduction was expressed.

CONCLUSIONS

Overbite reduction may result in suboptimal outcomes when using the Invisalign appliance unless remedial measures are employed. The deeper the initial overbite, the more challenging it is to achieve the prescribed posttreatment overbite.

Does Head Orientation Influence 3D Facial Imaging? A Study on Accuracy and Precision of Stereophotogrammetric Acquisition

This study investigates the reliability and precision of anthropometric measurements collected from 3D images and acquired under different conditions of head rotation. Various sources of error were examined, and the equivalence between craniofacial data generated from alternative head positions was assessed. 3D captures of a mannequin head were obtained with a stereophotogrammetric system (Face Shape 3D MaxiLine). Image acquisition was performed with no rotations and with various pitch, roll, and yaw angulations. On 3D images, 14 linear distances were measured. Various indices were used to quantify error magnitude, among them the acquisition error, the mean and the maximum intra- and inter-operator measurement error, repeatability and reproducibility error, the standard deviation, and the standard error of errors. Two one-sided tests (TOST) were performed to assess the equivalence between measurements recorded in different head angulations. The maximum intra-operator error was very low (0.336 mm), closely followed by the acquisition error (0.496 mm). The maximum inter-operator error was 0.532 mm, and the highest degree of error was found in reproducibility (0.890 mm). Anthropometric measurements from alternative acquisition conditions resulted in significantly equivalent TOST, with the exception of Zygion (l)–Tragion (l) and Cheek (l)–Tragion (l) distances measured with pitch angulation compared to no rotation position. Face Shape 3D Maxiline has sufficient accuracy for orthodontic and surgical use. Precision was not altered by head orientation, making the acquisition simpler and not constrained to a critical precision as in 2D photographs.

Predicting Maximal Lactate Steady State from Carminatti's Shuttle Run Test in Soccer Players

The objective of the present study was to determine the validity of Carminatti's shuttle run incremental test-T-Car derived parameters in estimating the maximal lactate steady state determined in shuttle run format. Eighteen soccer players performed a T-Car test, and several trials to determine the maximal lactate steady state. From T-Car were derived the heart rate deflection point, peak speed, maximal heart rate and parameters resulting from percentage of peak measures. The validity was accessed by Bland-Altman plots, linear regressions, and two one-sided tests of equivalence analysis. The results showed the speed at 80.4% of T-Car peak speed, the heart rate deflection point and the 91.4% of maximal heart rate were equivalent to maximal lactate steady state (Mean difference; ±90% compatibility interval; -0.8; ±1.5%, -0.4; ±1.1%, and 0.0; ±2.7%, respectively). Additionally, peak speed during the T-Car test was a stronger predictor of maximal lactate steady state (MLSS [km/h]=2.57+0.65 × sPeak; r=0.82 [90% CI; 0.62-0.92], standard error of the estimate=3.6%; 90% CI ×/÷1.4). Therefore, soccer players can use the T-Car derived parameters as a noninvasive and practical alternative to estimate the specific maximal lactate steady state for soccer.

Analysing the quality of Swiss National Forest Inventory measurements of woody species richness

BACKGROUND

Under ongoing climate and land-use change, biodiversity is continuously decreasing and monitoring biodiversity is becoming increasingly important. National Forest Inventory (NFI) programmes provide valuable time-series data on biodiversity and thus contribute to assessments of the state and trends in biodiversity, as well as ecosystem functioning. Data quality in this context is of paramount relevance, particularly for ensuring a meaningful interpretation of changes. The Swiss NFI revisits about 8%-10% of its sample plots regularly in repeat surveys to supervise the quality of fieldwork.

METHODS

We analysed the relevance of observer bias with equivalence tests, examined data quality objectives defined by the Swiss NFI instructors, and calculated the pseudo-turnover (PT) of species composition, that is, the percentage of species not observed by both teams. Three attributes of woody species richness from the latest Swiss NFI cycles (3 and 4) were analysed: occurrence of small tree and shrub species (1) on the sample plot and (2) at the forest edge, and (3) main shrub and trees species in the upper storey.

RESULTS

We found equivalent results between regular and repeat surveys for all attributes. Data quality, however, was significantly below expectations in all cases, that is, as much as 20%-30% below the expected data quality limit of 70%-80% (proportion of observations that should not deviate from a predefined threshold). PT values were about 10%-20%, and the PT of two out of three attributes decreased significantly in NFI4. This type of uncertainty - typically caused by a mixture of overlooking and misidentifying species - should be considered carefully when interpreting change figures on species richness estimates from NFI data.

CONCLUSIONS

Our results provide important information on the data quality achieved in Swiss NFIs in terms of the reproducibility of the collected data. The three applied approaches proved to be effective for evaluating the quality of plot-level species richness and composition data in forest inventories and other biodiversity monitoring programmes. As such, they could also be recommended for assessing the quality of biodiversity indices derived from monitoring data.

Stability of 40 cytokines/chemokines in chronically ill patients under different storage conditions

Numerous studies point to the utility of blood cytokine measurements in the diagnosis and treatment of human disease. Advances in detection allow robust multiplex analysis. However, cytokines are present at low levels and are produced and act in complex networks which can remain active in stored blood. A major barrier to the routine use of cytokines as clinical biomarkers is sample management prior to analysis. Studies on cytokine stability under storage frequently use 'spiked' normal control plasma or serum to generate detectable levels of the cytokines of interest. These conditions may oversimplify the reality of clinically complex samples and provide limited information regarding optimal management of whole blood samples prior to plasma separation. Cytokine stability has also been addressed previously using plasma from normal individuals under different conditions of anticoagulant use, storage time and temperature of storage. No studies have as yet been undertaken to address cytokine stability in critically ill patients which may differ from normal, healthy individuals due to underlying cofounders such as inflammation. To address these issues, we subjected samples from five patients exhibiting an inflammatory disease state to three storage extremes which might be encountered in a clinical setting, prior to analysis of 40 cytokines. Blood drawn into EDTA or ACD anticoagulant was immediately separated and plasma stored at -80 °C. Matched samples were stored as follows; whole blood overnight at room temperature, or whole blood or plasma stored 10 days at 4 °C. We used equivalence testing to determine the similarity of stored cytokine values to baseline values. In ACD plasma, Eotaxin, IL-6, IL-11, IL-15, IP10, MDC, MCP-1 met equivalence to baseline in all storage conditions while for EDTA plasma stored 10 days at 4 °C EGF, FGF2, Fractalkine, G-CSF, IL-1β, IL-5, IL-6, IL-7, IL-11, IP-10, TGFα and TNFα showed equivalence to baseline measurements. Intraclass Correlation Coefficients (ICC) were calculated and the following cytokines showed good to excellent agreement across all 4 storage conditions: Eotaxin, IL-5, IL-6, IL-11, IL-13, IP-10, MCP-1 and TNFα when collected in EDTA, and Eotaxin, IL-5, IL-6, IL-11, IL12-p40, IL-15, IP-10 and MCP-1 when collected in ACD. Five plasma cytokines were identified as being the least stable in both ACD and EDTA: IL-7, IL-9, IL12p70, RANTES, sCD40L, while IL-1β was identified as unstable stored in ACD plasma. This study identified several clinically important cytokines that are remarkably stable in blood and plasma, and some that stored poorly. To our knowledge, this is the first cytokine storage study to use medically unwell patient samples and equivalence testing to evaluate the stability of measured cytokine values after storage.

A critical view at the ISO 13528 and IUPAC's harmonized protocol approach for proficiency testing for homogeneity assessment for quantitative variables

Current PT sample homogeneity test has high risk of accepting heterogeneous.

No evidence for a bilingual executive function advantage in the nationally representative ABCD study

Learning a second language in childhood is inherently advantageous for communication. However, parents, educators and scientists have been interested in determining whether there are additional cognitive advantages. One of the most exciting yet controversial1 findings about bilinguals is a reported advantage for executive function. That is, several studies suggest that bilinguals perform better than monolinguals on tasks assessing cognitive abilities that are central to the voluntary control of thoughts and behaviours-the so-called 'executive functions' (for example, attention, inhibitory control, task switching and resolving conflict). Although a number of small-2-4 and large-sample5,6 studies have reported a bilingual executive function advantage (see refs. 7-9 for a review), there have been several failures to replicate these findings10-15, and recent meta-analyses have called into question the reliability of the original empirical claims8,9. Here we show, in a very large, demographically representative sample (n = 4,524) of 9- to 10-year-olds across the United States, that there is little evidence for a bilingual advantage for inhibitory control, attention and task switching, or cognitive flexibility, which are key aspects of executive function. We also replicate previously reported disadvantages in English vocabulary in bilinguals7,16,17. However, these English vocabulary differences are substantially mitigated when we account for individual differences in socioeconomic status or intelligence. In summary, notwithstanding the inherently positive benefits of learning a second language in childhood18, we found little evidence that it engenders additional benefits to executive function development.

Storage stability of commonly used haematological parameters at 33 °C: Electronic supplementary material available online for this article

Introduction

This study aimed to investigate the analytical bias in haematological parameters induced by storage at 33 ºC.

Materials and methods

Blood from the diversion pouch of 20 blood donors were collected in K₂EDTA vials and stored at 33 ºC. Readings from each vial were taken at 0, 4, 6, 12, 24, 48 and 72 hours after collection on the Sysmex XP-100 analyser (Sysmex Corporation, Kobe, Japan). The percent difference from the baseline readings were calculated and subjected to a Wilcoxon signed rank test at a Holm corrected significance level of 0.05. A median percent difference, which was statistically significant and greater than the maximum acceptable bias (taken from studies of biological variation), was taken as evidence of unacceptable shift. If the median shift was lesser than the maximum acceptable bias, two one-sided Wilcoxon signed rank tests for equivalence were used to determine whether the percent differences were significantly lesser than the maximum acceptable bias.

Results

Haemoglobin, red blood cell count, white blood cell count, mean corpuscular haemoglobin and lymphocyte count showed acceptable bias after storage for at least 24 hours at 33 ºC. Haematocrit, mean corpuscular volume, mean corpuscular haemoglobin concentration, platelet count and mean platelet volume showed unacceptable shift in less than 4 hours when stored at 33 ºC.

Conclusions

Since many haematological parameters show unacceptable bias within 4 hours of sample storage at 33 ºC, the recommended limit of time from collection to processing should be revised for areas where high environmental temperatures are common.